Bleeding Reduction

While plaque removal is fundamental to good oral hygiene, its significance diminishes if there is no corresponding reduction in bleeding to accompany it. Tissue that does not bleed is, in general, considered healthy and likely to remain that way.17 Bleeding, on the other hand, is strongly correlated with inflammation and consequently gingivitis.18

Several studies have evaluated the effect of automatic toothbrushes on bleeding and gingivitis. A 12- week study by Tritten and Armitage looked at the plaque index (PI), gingival index (GI), bleeding on probing (BOP), probing depth (PD), clinical attachment level (CAL), gingival crevicular fluid volume (GCF), and aspartame aminoaspertate (AST) levels in the GCF. Despite greater plaque reduction— 27% vs. 17%—there were no statistical differences in any of the bleeding comparisons between a sonic brush and manual toothbrush.4 Johnson and McInnes found similar results, also between a sonic and manual brush.8

Likewise, Stolz and Bay and van der Weijden et al. demonstrated equivalency between a manual brush and an oscillating device with respect to the reduction of gingivitis.5,6

Conversely, when a brush that combines oscillations with high speed in and out pulsations was compared to a manual toothbrush, the combination brush was statistically superior at day 90 in evaluating the GI. However, while statistically significant, the differences were very small—16% vs. 12%. Additionally, the bleeding index was similar for both products.10 Ainamo et al., despite no differences in PI between an oscillating brush and a manual brush, found the oscillating device had a statistically significant greater reduction in BOP—20.5% vs. 14.6%.7

Other studies that compare different products have varying results.19,20 Isaacs et al. found statistical significance for an ultra speed oscillating brush over a sonic brush when compared via the GI. However, when comparing bleeding sites, neither product could claim superiority—12.96% vs. 15.4%.19 Grossman et al. compared an oscillating unit and a sonic device and found non significant differences in both the PI and GI.20 Recently, Heasman et al. compared two different oscillating brushes and found minimal differences between them.21 Barnes et al. discovered similar results when comparing oscillating devices.22